Informatica shift field values to right

Question

I want to create a mapping in Informatica Powercenter for the following functionality :

Initial Target Table Values : Field 1 : 100, Field 2 : 200, Field 3 : 300, Field 4 : 400.

Now, if the record is updated with a new value, say 500... then field 1 value should be moved to field 2.. and field 2 to field 3... and field 3 to field 4... and the new value should be inserted in field 1. so the output would be :

Field 1 : 500, Field 2 : 100, Field 3 : 200, Field 4 : 300.

How can I achieve above functionality?!

Answer 1

The problem description is somewhat unclear, but it seems to be an interview question testing the knowledge of variable ports.

Refer to Prev column value display for a detailed explanation of port evaluation order. I will only reiterate two important points here:

1. The Integration Service evaluates ports in the following order: input ports -> variable ports -> output ports.
2. Ordering the variable ports properly is crucial, because the display order for variable ports is the same as the order in which the Integration Service evaluates each variable.

To solve the problem you need to define the a variable port for every input port with the following expressions:

in_Field1
in_Field2
in_Field3 
in_Field4

v_Field4 = v_Field3
v_Field3 = v_Field2
v_Field2 = v_Field1
v_Field1 = in_Field1

out_Field1 = v_Field1
out_Field2 = v_Field2
out_Field3 = v_Field3
out_Field4 = v_Field4